ArrayBoundCheck didn't say they never had to find out why a particular piece of code is the way it is, just that they didn't have to search through log messages.
For isntance, when you use "git blame" and similar tools, the log messages are not involved. You might end up reading the log message of the commit that was responsible for a change, but you didn't search log messages to get there.
In a project with poor commit messages, they will be of little use; reading them won't produce much value, let a lone searching.
Anyway, that seems like the best possible interpretation of the user's comment, anyway.